Objectives: This pilot study will establish the feasibility of conducting a study of a trauma- sensitive Hatha yoga protocol in female Veterans with posttraumatic stress disorder (PTSD) who experienced military sexual trauma (MST). As part of this study, we will characterize the PTSD symptom profile, psychiatric and medical co-morbidities, physical symptoms, and functional status of this population. In this study, we will evaluate several components of feasibility, including: recruitment and retention, data collection, and acceptability and implementation of the intervention protocol. Participants' adherence and yoga teachers' fidelity to the intervention will be evaluated as components of implementation feasibility. We also will evaluate specific biomarkers (cytokines) and psychophysiological markers (dark enhanced startle response and heart rate variability) as potential means of quantifying the beneficial effects of this intervention. Research Plan: This feasibility study will use mixed-methods to evaluate the implementation of a trauma-sensitive Hatha yoga intervention using a longitudinal pre-test- post-test design. Female Veterans will be recruited from a VAMC Trauma Recovery Program Women's/MST Program. Veterans with PTSD who report MST, chronic pain, and sleep disturbances will be offered the 10-week yoga intervention; an attention control support group will be offered in tandem. The target sample size is 40. Quantitative data will be collected prior to the intervention, after the fifth session, and 2 weeks and 3 months after the final session, yielding data on all participants for a total of 6 months. Focus groups will be conducted at these same time points as well as after the first yoga session. Methods: Variables include PTSD symptoms, psychiatric and medical co-morbidities, physical symptom profile, functional status, chronic pain, sleep disturbance and physiological responses, including psychophysiologic and inflammatory responses. These will be measured using symptom self-report measures; clinician administered psychological measures, e.g. CAPS; medical record data; and diagnostic measures, including wrist actigraphy, heart rate variability, dark-enhanced startle response, and inflammatory cytokines. Data regarding influences on retention and acceptability of the intervention will be obtained via focus groups, using nominal group process. Modifications to the recruitment process, retention strategies, and the intervention protocol will be made as indicated by these focus group qualitative data. Clinical Relevance: Assuming the results are favorable, this study will establish feasibility for a randomized controlled trial (RCT) with a primary aim of demonstrating that women who take part in the yoga intervention will have significantly reduced PTSD symptoms and pain, improved sleep, decreased physiological stress and improved functioning. These positive effects would likely improve quality of life (QOL) and minimize the significant medical consequences of PTSD, including cardiovascular and metabolic diseases. The larger clinical trial may provide sufficient evidence to support clinical guidelines for innovative complementary or alternative medicine (CAM) PTSD treatment for female Veterans which could be disseminated to VA Medical Centers nationwide.